As the airplane technology advances so to does the desire to make such available so that it may enjoy a wider use. In days gone by, for example, airplanes were launched and retrieved by various types of ships of the Navy fleet other than aircraft carriers. Today many such ships use helicopters as do certain non-military applications such as offshore oil rigs and other deep ocean installations. This is primarily due to a lack of an airplane that can alight and takeoff from the limited areas available at such places.
It is and has been readily recognized that inadequate range and speed limitations of helicopters make them at best a compromise with what is desired. This is to say nothing of the fact that as the work loads increase the helicopter size grows to where, even now, in some roles one must hover to take on and discharge loads. Furthermore, the complexities of helicopter construction and control lead to maintenance requirements that are burdensome economically.
It was no doubt with a recognition of a need to bring back fixed wing aircraft to these roles that many prior inventors toiled with limited success.
There was as many may recall the efforts by major airplane manufacturers to suggest that "tail-sitters" or "tilt-wings" may be solutions to the problems of finding a practical vertical takeoff and landing (VTOL) airplane having high speed and range performance of a fixed wing airplane. Neither of these approaches to a VTOL had more than a success in the media, i.e. they have not proven to be the practical design needed by either the military or commercial enterprises to justify adherence to other than the compromise of the helicopter operation.
It has been of particular note that in France in 1955 it was suggested one might employ rotatable powerplants on wings of a conventional airplane having conventional tail and wing controls to obtain a short takeoff and landing (STOL) airplane. This is shown by U.S. Pat. No. 2,971,725. Seven years later in 1962 Professor Calderon of Peru suggested that one may dispense with conventional tail pitch and yaw control surfaces by using a movable surface behind ducted fan means that pivot between a horizontal attitude to a vertical attitude out at the wing tips. This was disclosed to the public in U.S. Pat. No. 3,167,273. Next it was suggested in Germany in 1966 that one could take jet engines, two on each side, one of which was ahead and under and the other projecting above and behind a wing, and rotate same about an axis so that their thrust axis in the vertical position was equidistantly adjacent the airplane center of gravity point in the fuselage. This was disclosed by U.S. Pat. No. 3,469,803.
Presently the only known VTOL in use in the world is the British Harrier used by the United States Marine Corp. This airplane has jet propulsion means with a plurality of exhaust nozzles to either side of the airplane's fuselage. These nozzles rotate so as to provide horizontal and vertical thrust for the airplane. Therefore, one can fly the Harrier as a fixed wing airplane and operate in a VTOL mode as well.
With the exception of the disclosure by the assignee of this invention of a tail-sitter type airplane, for lack of a better self-coined label, shown by U.S. Pat. No. 3,966,142 this pretty much was and is the VTOL background for this invention. As for the airplane that is shown by assignee's patent aforesaid, there a propulsion means to either side of a fuselage, as by side pylons or podded wing units, is arranged to wash the empennage of the airplane to maximize control moments from rudder and elevator movements.